May is a fantastic month for families in New York City. Starting Memorial Day weekend, you can enjoy summer fun like beaches and amusement parks but without the sweltering heat you get later in the season. Plus there are free festivals, carnivals and street fairs practically everywhere you turn.

With so many great things going on in May, it's tough to figure out which events deserve a spot on your jam-packed schedule. But we do the work for you with our Go List, our carefully curated roundup of the absolute best things to do with kids in NYC throughout the month. Our May edition includes annual favorites my family and I try to attend every year, like the opening day Family Festival at Governors Island and Spring Kids Fest in Madison Square Park. Plus there are some brand-new happenings that sound pretty cool, like Grand Central Terminal's Centennial Parade of Trains and the New York Hall of Science's interactive Design Zone.

As always, if an event piques your interest, be sure to click through to our listing for all the details, including address and time. And although we say this every time, we think it bears repeating: In NYC, really cool things to do with kids often get booked up quickly. Last month, three of our April NYC Go List picks sold out weeks in advance. So buy your tickets ASAP or, in the case of FREE events, arrive as early as possible to avoid disappointment.

Now get your calendars ready! Here are the top 13 things to do with kids in New York City this May, nine of which are 100% FREE.

There are street fairs and then there are street fairs. We don't mean those random ones that sell irregular socks and fried Oreos; we're talking about true community festivals. Each one is unique and reflects the character of its neighborhood, and many feature rides, performances, activities and food. The hard part, of course, is knowing which ones are which, 'cause while we all love to stock up on cheap socks, we're not going to drag our family across town to do so.

We've gone through the city's list of festivals, street fairs and carnivals for the month of May and picked out our favorites from years past and some new events that sound promising. All of these fests are FREE or just a couple of bucks, and in most cases your dollars go to support a local charity or school, so you can feel good about spending money. In our research, we were bummed to learn that one of annual picks, the Hudson River Pageant, won't be happening this year. But there are 32 other awesome fests to choose from! You can find even more seasonal activities in our Spring Fun Guide.

Do you feel lucky? This week we have not one, not two but three great giveaways going on at Mommy Poppins. Enter to win an Earth Friendly Products gift basket chock-full of eco-friendly cleaning supplies; a professional portrait of your kids by artist Lori Nelson or a four pack of tickets to the Guggenheim Museum. Not only are the prizes eclectic, the methods of winning are as well. For the Earth Friendly Products and Lori Nelson portraits, all you need to do is enter to win. But for the Guggenheim giveaway, we're encouraging readers to take the kids to the museum's current exhibit Gutai, snap a pic and submit it to our Facebook or Pinterest pages. That giveaway is definitely the most fun and is totally in keeping with our site's mission of getting families out and about doing cool things with kids.

Speaking of fun family outings, festival season is in full swing, which inspired us to round up our top 25 FREE annual festivals. And would you believe three of our picks take place this very weekend?

Our other sites have also been busy sharing the best things to do this spring on Long Island, in New Jersey, Connecticut and beyond, but a few posts will be of particular interest to New York families. If your kids are begging to see the likes of Taylor Swift and One Direction live, NJ's got a roundup of concerts for tweens, most easily accessible from the city. Our LA site did an awesome post in honor of Screen-Free Week with 10 fun no-tech things to do with kids. And on a more somber note, our CT site has a heartfelt post about ways kids can volunteer in the wake of a tragedy. While some of the suggestions are local, there are also ideas that apply to families anywhere, like donating allowance or toys.

Here's what else we covered in NYC this week: